Analog Devices ADP121 Evaluation Board ADP121CB-2.5-EVALZ ADP121CB-2.5-EVALZ Fiche De Données
Codes de produits
ADP121CB-2.5-EVALZ
EVAL-ADP121
Rev. A | Page 5 of 8
LINE REGULATION
For line regulation measurements, the regulator’s output is
monitored while its input is varied. For good line regulation,
the output must change as little as possible with varying input
levels. To ensure that the device is not in dropout mode during
this measurement, V
monitored while its input is varied. For good line regulation,
the output must change as little as possible with varying input
levels. To ensure that the device is not in dropout mode during
this measurement, V
IN
must be varied between V
OUT
nominal
+ 0.5 V (or 2.3 V, whichever is greater) and V
IN
maximum. For
example, an
with a fixed 1.8 V output needs V
IN
to be
varied between 2.3 V and 5.5 V. This measurement can be
repeated under different load conditions. Figure 7 shows the
typical line regulation performance of the ADP121 with fixed
1.8 V output.
repeated under different load conditions. Figure 7 shows the
typical line regulation performance of the ADP121 with fixed
1.8 V output.
07
14
0-
0
04
1.806
1.802
1.804
1.800
1.796
1.794
1.798
V
OU
T
(V
)
2.3
2.7
3.1
3.5
3.9
4.3
4.7
5.1
5.5
V
IN
(V)
V
OUT
= 1.8V
T
A
= 25°C
LOAD = 10µA
LOAD = 100µA
LOAD = 1mA
LOAD = 10mA
LOAD = 50mA
LOAD = 100mA
LOAD = 100µA
LOAD = 1mA
LOAD = 10mA
LOAD = 50mA
LOAD = 100mA
Figure 7. Output Voltage vs. Input Voltage
LOAD REGULATION
For load regulation measurements, the regulator’s output is
monitored while the load is varied. For good load regulation,
the output must change as little as possible with varying loads.
The input voltage must be held constant during this measure-
ment. The load current can be varied from 0 mA to 150 mA.
Figure 8 shows the typical load regulation performance of the
ADP121 with fixed 1.8 V output for an input voltage of 2.3 V.
monitored while the load is varied. For good load regulation,
the output must change as little as possible with varying loads.
The input voltage must be held constant during this measure-
ment. The load current can be varied from 0 mA to 150 mA.
Figure 8 shows the typical load regulation performance of the
ADP121 with fixed 1.8 V output for an input voltage of 2.3 V.
1.806
1.804
1.802
1.800
1.798
1.796
1.794
0.01
0.1
1
10
100
1000
I
LOAD
(mA)
V
OU
T
(V
)
07
14
0-
00
5
V
OUT
= 1.8V
V
IN
= 2.3V
T
A
= 25°C
Figure 8. Output Voltage vs. Load Current
DROPOUT VOLTAGE
Dropout voltage can be measured using the configuration
shown in Figure 5 and Figure 6. Dropout voltage is defined as
the input-to-output voltage differential when the input voltage
is set to the nominal output voltage. This applies only for output
voltages above 2.3 V. Dropout voltage increases with larger loads.
For more accurate measurements, a second voltmeter can be
used to monitor the input voltage across the input capacitor.
The input supply voltage may need to be adjusted to account for
IR drops, especially if large load currents are used. Figure 9 and
Figure 10 show the typical curves of dropout voltage measure-
ments with different load currents for different output voltages.
shown in Figure 5 and Figure 6. Dropout voltage is defined as
the input-to-output voltage differential when the input voltage
is set to the nominal output voltage. This applies only for output
voltages above 2.3 V. Dropout voltage increases with larger loads.
For more accurate measurements, a second voltmeter can be
used to monitor the input voltage across the input capacitor.
The input supply voltage may need to be adjusted to account for
IR drops, especially if large load currents are used. Figure 9 and
Figure 10 show the typical curves of dropout voltage measure-
ments with different load currents for different output voltages.
120
140
160
180
100
80
60
40
20
0
1
10
100
1000
I
LOAD
(mA)
V
DR
O
P
O
UT
(m
V
)
07
14
0-
0
06
T
A
= 25°C
V
OUT
= 3.3V
V
OUT
= 2.5V
Figure 9. TSOT Dropout Voltage vs. Load Current
100
80
60
40
140
120
20
0
1
10
100
1000
I
LOAD
(mA)
V
DR
O
P
O
UT
(m
V)
07
14
0-
0
13
T
A
= 25°C
V
OUT
= 3.3V
V
OUT
= 2.5V
Figure 10. WLCSP Dropout Voltage vs. Load Current